The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
During manufacturing, a gear, such as a ring gear for a vehicular transmission, undergoes a series of operations to form high precision datum surfaces and gear teeth. Generally, gear teeth are machined on a blank material to form an unfinished gear that then undergoes one or more heat treatments to strengthen the material of the gear. Some heat treatments can distort the tooth flanks and the datum of the gear, and therefore, the unfinished gear is hard machined by a machining tool to form the high precision datum surface and gear teeth.
Prior to finishing the gear teeth, the datum surface used to measure a mounting distance of the teeth is hard machined by, for example, a pitch chuck three-jaw chucks, or a device having a bore expansion collet, an outside diameter expansion collet, and an outside diameter chuck. These machining methods can impart clamping errors and inhibit accurate setting of the mounting distance because of the variations between gears and the clamping location. In another machining method, the amount of material to remove is first determined using an over-ball contact technique in which a mounting distance is measured at one or more locations along the unfinished gear. This measurement is then used to determine an average stock removal for the gear. Such technique is time consuming and requires different measurement instruments for different gear tooth geometry. These and other issues are addressed by the teaching of the present disclosure.